/**
 * This is most complex and difficult device.
 * It realize "read through write" paradigm. This is not standard, but
 * most of I2C devices use this paradigm.
 * You must write to device reading address, send restart to bus,
 * and then begin reading process.
 */

#include <stdlib.h>

#include "ch.h"
#include "hal.h"

#include "lis3.h"


#define lis3_addr 0b0011101


/* buffers */
static uint8_t accel_rx_data[ACCEL_RX_DEPTH];
static uint8_t accel_tx_data[ACCEL_TX_DEPTH];

static int16_t acceleration_x = 0;
static int16_t acceleration_y = 0;
static int16_t acceleration_z = 0;


/**
 * Init function. Here we will also start personal serving thread.
 */
int init_lis3(void){
  /* configure accelerometer */
  accel_tx_data[0] = ACCEL_CTRL_REG1 | AUTO_INCREMENT_BIT; /* register address */
  accel_tx_data[1] = 0b11100111;
  accel_tx_data[2] = 0b01000001;
  accel_tx_data[3] = 0b00000000;

  /* sending */
  i2cAcquireBus(&I2CD1);
  i2cMasterTransmit(&I2CD1, lis3_addr, accel_tx_data, 4, accel_rx_data, 0);
  i2cReleaseBus(&I2CD1);
  return 0;
}

/**
 *
 */
void request_acceleration_data(void){
  accel_tx_data[0] = ACCEL_OUT_DATA | AUTO_INCREMENT_BIT; // register address
  i2cAcquireBus(&I2CD1);
  i2cMasterTransmit(&I2CD1, lis3_addr, accel_tx_data, 1, accel_rx_data, 6);
  i2cReleaseBus(&I2CD1);

  acceleration_x = accel_rx_data[0] + (accel_rx_data[1] << 8);
  acceleration_y = accel_rx_data[2] + (accel_rx_data[3] << 8);
  acceleration_z = accel_rx_data[4] + (accel_rx_data[5] << 8);
}